Cabin in the Woods
War of the Worlds (1953)
Children of Men
28 Days/Weeks Later (if zombie movies count)
Tintinnabulation - first place (Free Spirit)
Comet Q - second place (Quick and Risqué Sex)
Amnesia - third place (Le Noir Erotique)
World's end
Dawn of the dead
Icarus4 made an excellent choice. "On the Beach" (1959 version with Gregory Peck and Ava Gardner, based on Nevil Shute's novel) shows that humans are more than capable of destroying the world without any outside help.
Also, "When Worlds Collide" (1951). A 1950s SciFi classic.
"It seemed like a nice neighborhood to have bad habits in.” Raymond Chandler
The Gin Rickey Singularity -- Dirty Talk competition entry
28 Days Later
Night of the Living Dead (1968)
The World's End
Dogma (Does that count? They are trying to save all of mankind so I say yes.)
Terminator 1 and 2 (Again, they are trying to save mankind so Dogma rules from above apply?)
I have a new story out! Wish You Were Here A teasing sub may I have pushed too far, but the punishment is oh so sweet.
If you haven't already, please check out my story with leftlingula. A husband and wife rediscovered each other and It all started with one simple word...
Nightshade Part 1 & Nightshade: Part 2